Samsung Galaxy Watch 4 Classic User Manual page 43

Apps and features
Recording and sending a voice message
You can send a voice file after recording what you want to say.
On the message input screen, tap
Deleting messages
1
Tap (Messages) on the Apps screen.
2
Scroll through the message list, and then select a contact to view your conversations.
3
Tap and hold a message, then tap Delete.
To delete multiple messages, tap and hold a message, select messages you want to delete,
and then tap Delete.
The message will be deleted both from the Watch and the connected smartphone.
and say what you want to be sent.
42
Stop recording voice.